25829821 has 2 divisors, whose sum is σ = 25829822. Its totient is φ = 25829820.

The previous prime is 25829819. The next prime is 25829831. The reversal of 25829821 is 12892852.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18748900 + 7080921 = 4330^2 + 2661^2 .

It is a cyclic number.

It is not a de Polignac number, because 25829821 - 2¹ = 25829819 is a prime.

Together with 25829819, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25829831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12914910 + 12914911.

It is an arithmetic number, because the mean of its divisors is an integer number (12914911).

Almost surely, 2^25829821 is an apocalyptic number.

It is an amenable number.

25829821 is a deficient number, since it is larger than the sum of its proper divisors (1).

25829821 is an equidigital number, since it uses as much as digits as its factorization.

25829821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23040, while the sum is 37.

The square root of 25829821 is about 5082.3046937389. The cubic root of 25829821 is about 295.6018394161.

It can be divided in two parts, 2582 and 9821, that added together give a triangular number (12403 = T₁₅₇).

The spelling of 25829821 in words is "twenty-five million, eight hundred twenty-nine thousand, eight hundred twenty-one".